In general terms, a tether is a cord that anchors something movable to a reference point which may be fixed or moving. There are a number of applications for tethers, e.g., balloons, kites, anchors, and towing. Tethers employable in space share the same general functionality as terrestrial tethers, i.e., they both anchor a movable object to a reference point, but, due to the space environment, tethers employable in space often include special design features.
An exemplary space tether was developed by Professors Yoshiki Yamagiwa and Masahiro Nomi of Shizuoka University, Hamamatsu, Japan as part of a “space tethered autonomous robotic satellite-cube” (STARS-C). (See: The Asahi Shimbin, Jul. 6, 2016, “University Orbiter Set to Lift Space Elevator Technology.”) STARS-C employs a tether measuring 100 meters long to connect two 10-centimeter cubes in low Earth orbit. The tether has a diameter of 0.4 millimeters and is made of Kevlar.
A series of failure resistant tethers employable in space have been described by Hoyt et al., e.g., U.S. Pat. Nos. 6,386,484; 6,290,186; 6,286,788; 6,260,807; 6,173,922; 6,116,544; and 6,419,191. Taken together, the tether design features disclosed in Hoyt's patent disclosures have significantly mitigated the potentially dire consequences of tether failure in space.
A problem not adequately addressed in the prior art was the fact that the transport of a fully functional tether into orbit is limited by the size and mass of the tether and the availability of transport rockets having the load capacity to transport the tether into space, particularly transport into a high altitude geosynchronous orbit. What was needed was a tether design that facilitated transport of the tether into space.